Oil burner



Much 10, 1942- w. B. sHE-PPERQ ETAL v 2,275,689

OIL BURNER Filed Feb. '21, 1940 2 Sheets-Sheff. l

I NVENToRs i WILLIAM B. SHEPPEBD,

39 Lew/5 .5002

HTTORNE Y,

Much 1o, i942.

w. B. sHEPPERD lrru.v

OIL BURNER Filed Feb. 21, 1940 2 Sheets-Sheet 2 R l Vl. T www W. Nima m VS//WW N-L Mm mE LL H. w w

Patented Mar.- 10, 1942 OIL BURNER,

William B. Shepperd and Lewis L. Scott, St. Louis, Mo.; said Sliepperd assignor to said Scott L Application February 21, 1940, Serial No. 320,6138` 1 Claim.

This invention relates to oil burners of the general type shown in Patent 2,117,512, dated May 17, 1938, issued to Lewis L. Scott, and has for its object adapting this type of oil burner with certain auxiliary devices. including a preheating device so as to enable it to burnl the very heavy fuel oils.

One of the objects of this invention relates to a means of preventing the oil burner from being turned on until the oil has been pre-heated to a definite temperature that will insure proper spraying and ignition of the oil.

Another object is to provide a compound preheater so that one part of the pre-heater will heat the oil before it goes into the oil filter and oil pump, and the other part of the pre-heater will provide hot oil that goes direct to the fuel spray nozzle. y

v Another object is to provide a means whereb the oil is pre-heated by an electric heater during the period prior to operation of the burner, but after the burner is in operation the pre-heating of the oil will be done by heat from the oil fire so that no electric current will be used in preheating the oil during the running period.

Another object is to provide a tank for the pre-heater, which will enclose the oil heating coils, and which tank will contain a liquid having a boiling point at atmospheric pressure substantially higher than 300 Fahrenheit.

Another object is to so connect the pre-heater with the spray nozzle that the nozzle pipe and nozzle will be heated from the pre-heater by conduction through metal.

Another object is to provide Van arrangement whereby during the operating period of the burner any excess oil that is heated above the necessary temperature to get the proper spray will be returned to the oil tank, and in this way prevent over-heating of the oil during the running period of the burner when heat is supplied by the oil fire.

Various other objects and advantages will be apparent from the following description and the novel features will be pointed out in the appended claim.

The accompanying drawings illustrate our in- Y vention.

Referring now to the drawings, Figure 1 shows a plan view of our oil burner showing among other things the pre-heater tank setting on top of an extension of the air blower housing.

Figure 2 shows a front elevation of the preheater tank, the oil filter, and the front end of the burner nozzle, together with pipes connecting to the pre-heater tank for producing heat within the tank from the oil re.

Figure 3 shows a sectional view of the preheater tank.

Figure 4 shows a View of the automatic control device which controls the temperature within the pre-heater tank and also prevents the burner from starting until a certain temperature is reached within the pre-heater tank.

Figure 5 is an enlarged view of the mercury switch shown in Figure 4.

Figure 6 is a diagrammatic view of the oil flow from the oil tank through the pre-heater coils to the spray nozzle and also the return oil to the tank.

Figure 7 is a diagrammatic drawing of the electric wiring.

Referring now to the drawings, the numeral I indicates an electric motor which is secured to the blower housing 2, which motor operates a fan, not shown, within the blower housing 2, and an air compressor 3 and oil pump 4. The oil pump and air compressor is of the same identical construction as shown in Patent 2,117,512, dated May 17, 1938, before mentioned, and the oil burner'generally is the same as described in thc above mentioned patent, with the exception of the addition of the oil pre-heating device and the control of said pre-heating device.

The numeral 5 indicates an oil pre-heater tank, which tank contains a liquid as before mentioned, and which also contains apre-heating coil 6 and other pre-heating coil 1, an electric pre-heater 8, and a bulb 9 leading to a control device whichv will be later described.

The pipe I0 is connected to the lower part of the tank and runs down around the forward part of the oil burner blast tube II, forming a loop I2 around said blast tube and running back to the tank 5 through the pipe I3. It will be noted that the tank 5 is elevated above the blast tube II so that when heat from the oil re is radiated to the pipe I2, the liquid in said tank will circulate by thermosyphon action through the pipes Il), I2 and I3, and will heat up the liquid y contained in the tank 5.

We will now describe the path of the oil. Referring to Figure 6, the numeral I4 indicates an oil tank. The pipe I5 connecting with the oil tank I4 runs to the heater coil 6y contained in the tank 5, and vfrom the coil 6 to the oil filter I6, through an electric solenoid valve I1, to the oil pump l, through the pipe I8, to the heater coil 1, through the pipe I9 to the oil spray nozzle as described in detail in the patent above referred to.

The pipe 20 is arranged to by-pass surplus oil from the pump 4 to the tank I4. 'Ihe numeral 2| indicates a check valve in the return pipe line 20. The numeral 22 indicates a well known type of thermally operated valve which is normally open, and which permits the by-passed oil from the pipe 20 to return to the suction side of the pump 4 while open, however, this valve is adapted to close at a certain pre-determined high temperature so that any excess heated oil will be returned to the tank I4, and the heat will be radiated from said tank. It will be noted that on an initial start heat is supplied to the liquid in the pre-heater vtank 5 by the electric preheater 8, and that after the oil burner is in operation heat will be supplied to the pipe I2 by the oil name, which will supply the necessary heat to the liquid in the tank 5. Particular attention is called to the fact that the oil pump when operating pumps oil at its maximum capacity, and the pre-heater is arranged to take care ofA pre-heating all of the oil that the pump can pump; however, when the burner might be operating and burning say one gallon per hour through the spray nozzle and the pump had a total capacity of six gallons per hour, the remaining five gallons would be by-passed back to the tank I4. If, on the other hand, the spray nozzle was actually passing and burning six gallons per hour, then there would be substantially no oil by-passed to the tank I4; however, regardless of whether one gallon of oil or-six gallons of oil were being passed through the spray nozzle and being burned, the proper pre-heat of the oil would be maintained within practical limits, so that no extra control devices would be required when pre-heating the liquid in the tank 5, bypre-heat from the oil re. It is obvious that pre-heat directly from the oil re can be furnished in a number o'f ways; for example, the products of combustion from the combustion chamber could be diverted and .passed over the outside of the tank 5, or said tank 5 could be arranged in a bypass flue from the heating furnace, and thermostatic means could be arranged to control the amount of hot gases passing over the tank 5. The means of heating the liquid in the tank directly from the oil fire such as before described should not be confused with an indirect method of heating which might be supplied, if a steam or hot water boiler were being used and heat from the oil re were supplied to such boiler. This particular feature of our invention relates to getting heat direct `from the oil iire, to furnish the necessary pre-heating of the oil during the operating period of the burner and thereby doing away with the necessity of electric pre-heat during. this period. In many instances these oil burners are used in warm air furnaces for heating houses, and the only method that has ever been used to our knowledge for pre-heating oil in a case of this kind would be a straight electric pre-heater.

We will now describe the electric circuit and runs through the limit switch 29, which switchv is commonly used on a heating plant; for example, in the case of a steam boiler for limiting the pressure developed in the boiler, and is arranged to break the electric circuit when a pre-determined steam pressure is reached in the boiler. The wire runs to the center terminal on the mercury switch 33, and when said switch is in the position shown in Figure 4, electric current will pass through the mercury to the left hand terminal of the mercury switch 32, through the.

electric pre-heater 8 contained in the tank 5, and then through wire 34, through fuse 21 and switch 25,.back to the mainpower wire 24. When the mercury switch 33 is in the position shown in Figure 5, the electric pre-heater 8 is still on, and the mercury in said switch also connects terminal 3I of said mercury switch, which will permit the'current to flow through the room thermostat to the motor I and solenoid valve I1, and back to the other side of the line through wire 36. The wires 3l and 38 run to the electric spark ignition transformer 39, which supplies the spark for the electric ignition device fully described in the patent before referred to. Under the above condition, the motor I will start and oil from the spray nozzle will be ignited in the well known manner as described in the above mentioned patent.

When the liquid in the tank 5 reaches a predetermined temperature, the liquid in the bulb 9 will expand and operate the bellows 40. The mercury switch 33 is supported by a member 4I which is pivoted at 42 in the housing 43. The member 4I has a projecting arm 44 to which connects a spring 45, which spring is attached to the y housing 43. The bellows has a projecting arm 46 which engages the arm 44, and when the liquid in the bellows 40 expands. said arm will move upward and cause the mercury switch 33 to assume the position shown in Figure 5, and then to assume a position that will tilt the mercury tube 33 to the right, thereby breaking the circuit to the wire 32, and shutting off current to the 'temperature in the 'tank 5 which pre-heats the oil for the burner will-be maintained from the oil re.

We claim:

In an oil Aburner for burning heavy oils for heating a iiuid, a pump for pumping and delivering oil to the burner atomizer, an oil preheater for heating the oil going to the atomizer comprising a tank containing a liquid having a higher boiling point than water, a heater having a source of heat independent o! the oil flame tor heating the liquid in the tank, automatic means respon- 'sive to the temperature of the liquid in the tank for controlling the operation oi.' said heater, an oil pipe in thermal communication with the liquid in the tank, a pipe containing liquid from the tank exposed to radiant heat of the oil llame and so connected to the tank as -to heat the liquid in the tank. v

. WILLIAM B. SHEPPERD.

LEWIS L. SCOTT. 

